module Assay

  module RSpec

    #
    # TODO: Note this is the code from RSpec for `#have`. It needs to rewritten
    # into a form usable by Assay.
    #
    class Have

      def initialize(expected, relativity=:exactly)
        @expected = case expected
                    when :no then 0
                    when String then expected.to_i
                    else expected
                    end
        @relativity = relativity
        @actual = @collection_name = @plural_collection_name = nil
      end

      def relativities
        @relativities ||= {
          :exactly => "",
          :at_least => "at least ",
          :at_most => "at most "
        }
      end

      def matches?(collection_or_owner)
        collection = determine_collection(collection_or_owner)
        query_method = determine_query_method(collection)
        raise not_a_collection unless query_method
        @actual = collection.send(query_method)
        case @relativity
        when :at_least then @actual >= @expected
        when :at_most  then @actual <= @expected
        else                @actual == @expected
        end
      end

      alias_method :pass?, :matches?
      alias_method :===,   :matches?
      alias_method :=~,    :matches?


      def determine_collection(collection_or_owner)
        if collection_or_owner.respond_to?(@collection_name)
          collection_or_owner.send(@collection_name, *@args, &@block)
        elsif (@plural_collection_name && collection_or_owner.respond_to?(@plural_collection_name))
          collection_or_owner.send(@plural_collection_name, *@args, &@block)
        elsif determine_query_method(collection_or_owner)
          collection_or_owner
        else
          collection_or_owner.send(@collection_name, *@args, &@block)
        end
      end

      def determine_query_method(collection)
        [:size, :length, :count].detect {|m| collection.respond_to?(m)}
      end

      def not_a_collection
        "expected #{@collection_name} to be a collection but it does not respond to #length, #size or #count"
      end

      def failure_message_for_should
        "expected #{relative_expectation} #{@collection_name}, got #{@actual}"
      end

      def failure_message_for_should_not
        if @relativity == :exactly
          return "expected target not to have #{@expected} #{@collection_name}, got #{@actual}"
        elsif @relativity == :at_most
          return <<-EOF
Isn't life confusing enough?
Instead of having to figure out the meaning of this:
should_not have_at_most(#{@expected}).#{@collection_name}
We recommend that you use this instead:
should have_at_least(#{@expected + 1}).#{@collection_name}
EOF
        elsif @relativity == :at_least
          return <<-EOF
Isn't life confusing enough?
Instead of having to figure out the meaning of this:
should_not have_at_least(#{@expected}).#{@collection_name}
We recommend that you use this instead:
should have_at_most(#{@expected - 1}).#{@collection_name}
EOF
        end
      end

      def description
        "have #{relative_expectation} #{@collection_name}"
      end

      def respond_to?(m)
        @expected.respond_to?(m) || super
      end

      private

      def method_missing(method, *args, &block)
        @collection_name = method
        if inflector = (defined?(ActiveSupport::Inflector) && ActiveSupport::Inflector.respond_to?(:pluralize) ? ActiveSupport::Inflector : (defined?(Inflector) ? Inflector : nil))
          @plural_collection_name = inflector.pluralize(method.to_s)
        end
        @args = args
        @block = block
        self
      end

      def relative_expectation
        "#{relativities[@relativity]}#{@expected}"
      end

    end

  end

end
